Compressed-air pump.



l ill M. L. MITCHELL.

COMPRESSED AIR PUMP.

(.Apphcahon led Jan 2S 1899 j o@ @v @m (No Model.)

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@mnh/masks MARCUS L. MITCHELL.

$3715. HIOLHMJO Patented Aug. I, i899. M. L. MITCHELL.

COMPRESSED AIR PUMP. (Appucluion mea Jan. 2s, 1399.)

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SXw/L No. 629,867. Patented Aug. l, m99. m. L. mTcHELL.

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(Application led Jan. 28, 1899.) Y (No Model.) 5 Sheets-Sheet 3,

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No. 629,867` Patented Aug. I, |899. M. L. MITCHELL.

COMPRESSED AIB PUMP.

(Application med Jan. 2B, 1899.)

(No Model.) 5 Sheets-Sheet 4.

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CQMPRESSED AIR PUMP.

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UNITED' S'inrrnsV PATENT Orifice.

f 'Marions L. MITCHELL, or ST. LOUIS, MISSOURI,

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i 'SPECIFICATION formingpart of `Iiiters Patent NO. 629,867, datedAugust 1, 1899;

.y Application filed January 1899, Serial No. 703,691. (No model.) l

To a/ZZ 'whom/lit may con/cern.-

Be it known ,that 1,A MARCUS L. MITCHELL, a citizen of the United Statesof America, re-

siding-at St. Louis, in the State ofvMissouri,

have invented a certain new and useful Compressed-Air Pump, vof whichthe following is such a full, clear, and exact descriptionas will enableany one skilled in the art to which it appertains to make and use thesame, reference being had tothe accompanying drawings, forming partofthisspecioation. e

My inventiony relates to that'class of pumps in which the Water is firstallowed to enter a suitable chamber through a valved inlet and then isforced out bythe admission of compressed air to said chamber.

My pump is especially adapted to be used with two chambers, so that theWater is forced out of one while it is entering the other, thus giving acontinuous or practically continuous flow. Many features of myinvention, however, are applicable to pumps having but a single chamber.Pumps of this class are usually submerged in the water, so that theWater-4 enters them by gravity.

My invention consists .inso arranging the` main Avalvethat the admissionof vair can be I cut off from one chamber beforeV the exhaust is cut odfrom the other chamber, so as to prevent waste ofV air and also to allowthe said latter chamber to be completely iilled with water before thecompressed air is admitted to it.

My invention also consists in various other novel features and detailsof construction, all

of which will be described in the following' specification and pointedont in the Vclaims a dined hereto.

1n the accompanying drawingsmfhich illustrate one formofpump made inaccordance l with my invention, Figure l is avertical .1on-

gitudinall' central section. Fig. 2 is an enlarged view of a portion ofthe valve mechanism shown in Fig. 1. Fig. 3 is an enlarged Viewofthemain valve shown in Fig. 2, but in a different position. Fig. e isa section on the line i #l of Fig. 2.- Fig.:5` is a top plan view of oneof theparts shown in Figs.'2 and 4. Fig. 6 is a section on the line 6 6of Fig. 7 Fig. 7isj a topplan View of one of the discharge-valvecasings.` Fig. S is 'a top plan view of one of the plaies carrying thedis Fig. 17 is aviewshowing some ofthe pipe connections, and Fig. 18,Sheet 4, is atop plan viewqof one4 of the'lvalves shown in Fig. 16.`Lille marks of reference refer to similar parts in the several views ofthe'drawings.

2O represents a cylinderwhich is' divided into two chambers 2l and 22 bya partition 23'. Each of the chambers 21 and 22 is provided withinlet-openings 24. Secured around the inlet-openings 24 of each of thechambers is an inlet-valve casing 25." (Shown in detail in Fig. 9.)Secured to the bottom of the casing 25 is a plate 26, which carries theinlet-valves 27. Each of the valves 27 consists of a suitable metal disk28, which is adapted to iit tightly in a suitable opening in the plate26 and is provided with openings 30. Secured inthecenter of the disk 28is a rod 31, at the upper end'of which is a head 32. Sliding on the rod31 isa disk 33, of rubber or other suitable material, which is adaptedto close the openings v30. The head 32 limits the upward movement Iofthe dish 33. I prefer to use a number ofthese valves 27 in place of onelarge valve, as the necessary amount of vWater can thus beadmitted 'withless movement of the valveso that the valve acts more quickly .and alsocauses less jar Ain seating.

Extending upward from near the bottoni of each vof thechambers 21v and22 is'a pipe 35,

.Fig.v v1, which communicates with-adischargevalve casing 36. Containedin the discharge- 'valve casing 36 is a platel37, which'carries a numberof discharge-valves 3S. The discharge-valves 38 are constructcdlike theinlet-Valves 27,`previously described, and hence it is not necessary todescribe their construction in detail. I use a number of them for thereasons given `in connection with the valves 27. kLeading from each' ofthe dis- Fig. l2 is a bottom plan view ofone ICO' charge-valve casingsBGis a pipe 39; The two pipes 39 may be connected to a common/pipe 40,which is then led to the point where it is desired to discharge thewater.

Secured to the cylinder 2O i's a casting 42, which is provided with twoports 43, one of which communicates with each of the chambers 21 and 22and alternately serves as a supply and a discharge port for thecompressed air. The casting 42 is also provided with an exhaust-port 44,which is alternately connected first with one and then the other of thetwo ports 43. The casting 42 has also formed in it two grooves 45, Fig.5, for the reception of air-pipes to be hereinafter described. Securedto the casting 42 is a main-valve casing 46, Figs. 1, 2, 4, and 16, andbetween the said parts is held a valve-plate 47. Sliding in thevalve-casing 46 is apiston 48. The central portion of the piston 48 iscomposed of two webs 49, Fig. 4, which webs have formed in their underedges recesses 41 for the reception of aslide-valve 50, which controlsthe ports 43 and 44,which are continued upwardly through the valve-plate47. The recesses 41 are of such a length that the valve 50 will havesome play, and hence will not have as much movement as the piston 48.Each end of the valve-casing 46 communicates by way of an auxiliary portor by-pass 51 with one' of the ports 43, and in each of the auxiliaryports 51 is placed a valve 52, preferably in the form of a small rubberball which seats upwardly and closesthe contracted passage 53, whichconnects the ends of the casing with the ports 51.

The slide-valve 50 should be formed, as shown in Fig. 3, so that it willclose the port 43 which has been in communication with the live airbefore the other port 43 is cut od from the exhaust. This is best done,as is shown in Fig. 3, by having the opening 54 in the slide-valve 50 ofsuch length that when one of the ports 43 is closed an opening 55 willbe left connecting the other port 43 with the exhaust-port 44.Compressed air is admitted to the central portion of the valvecasing 46through an opening 56. (Shown in Figs. 2 and 4.) This opening isconnected with `a suitable supply-pipe 56A, which leads either directlyor indirectly to the air compressoror reservoir for furnishing thecompressed air.

The piston 48 should be of such alength that when it is in its centralposition as shown in Fig. 2, it will cover both vthe contracted pas-ysages 53, leading to the ports 51. I prefer to line theends of thevalve-casing 46 with cylinders 57, of bronze, brass, or other suitablematerialwhich is not easily affected by water. The ends of thevalve-casing 46 are closed by heads 58, which maybe held in position bycross-bars 59 and bolts 60, Figs. 2 and 16, or any other suitable means.

Formed in each of the ports 43, preferably some distance above the topof the cylinder 20, are valve-seats 62, Figs. 1 and 2. 63, Fig. 1, areconical valves, of rubber or other suitable material, which are adaptedto seat against the valve-seats 62. Each of these valves 63 is carriedby a ioat 64, preferably made of hollow metal. The ioats 64 are guidedin their upward-and-downward movement by suitable rods 65. The rods 65should extend to near the bottom of the cylinder 20, so as to allow thevalves 63 to be at such a distancefrom their seats that there will be nodanger of the outgoing air seating them when the air is exhausted. Theobj ect of the valves 63 is to prevent the water from passing up throughone of the ports 43 into the exhaust-pipe in case the chamber connectedwith the exhaust should become filled before the other chamber wasemptied.

Secured to the cylinder 2O are two primary valves 67, one of whichcommunicates with the chamber 2l and the other with chamber 22. Each ofthese valves 67 consists of a box or chest 68, Figs. 2, 11, and v14,from which projects a suitable cylinder 69. Leading from the cylinder 69of the Valve 67 which is in communication with the chamber 2l is a pipe70, (see also Figs. 1, 4, and 16,) which communicates' with the oppositeend of the main-valve chamber 46, and leading from the cylinder 69 ofthe other valve'67 to the other end of the main-valve chamber 46 is asimilar pipe 71. The pipes 70 and 71 lie in the grooves 45 in the plate42, Figs. 4 and 5. In each of the cylinders 69 is a piston 72, which hasformed in it two reduced portions 73, Figs. 2 and 11. In each of thecylinders 69, at the outer side of the pipes 70 and 7l, respectively, isformed an exhaust-port 74 and at the inner side of said pipes asupply-port 75. Each of these ports 74 and 75 is adapted to bealternately connected with one of the pipes 70 or 71 by t-he movement ofthe piston 72. 76, Figs. 16, 17, and 18, is an air-supply pipe havingtwo lateral branches which communicate with the ports 75. Theexhaustports 74 are preferably connected with an exf haust-pipe 76A.Connecting .the outer end of the cylinder 69 with the box or chest 68 isa suitable port 77, Fig. 2. The object of this port 77 is to balance thepiston 72, so that the pressure from the chambers 2l and 22 will notaffect the movement of said piston. `The end of each of the cylinders 69is preferably supplied with a screw-plug 78 to admit of the removal ofthe piston 72,' and the box or casing 68 is also preferably suppliedwith a screw-plug 7 9 to give access to the interior thereof. Each ofthe pistons 72 is connected, by means of a link 80, with one end of abellcrank lever 81, Figs. l, 2, 11, and14, which projects upwardly intothe interior of the box 68. The bell-crank lever 81 is pivoted, by meansof a pin 82, Figs. 14 and 15, between two downwardly-projecting arms 83,carried by the box 68. The lower end of the bellcrank lever 8l isprovided with two studs or pins 84 and 85, Fig. 13. The pin 84is adaptedto Workin a slot 86, formed in the upper end of a rod 87, the lower endof which is pivoted to a bar 88, Fig. 1, one end of which is pivoted 'toan upright 89 and the other of which is at- IOO llc.

cease? v "radicato a weight 9o. Thesrud 0ipin S515 adapted to come incontact with a rod 91,one end of which turns loosely on the hub 92 ofthe bell-crank lever S1 and the other end of which is attached to afloat 93. The weights 90 are in the form of floats, but have only sufflcient buoyancy to sustain their own weight,so

as not to counteract the effect of the floats 93.

Depending from the top of the cylinder 20 are two stops 94, which limitthe downward movement of the iioats 93, and two similar stops 95,projecting upwardly from the bottom of the cylinder 20, limit the upwardmovement of the weights 90. In order to economize space, I provide domes100, into which the floats 93 project when in their highest position.These domes 100 are preferably formed integral with the lower parts ofthe discharge-valve casings 36. By the use of the domes 100 the chambers21 and 22 are allowed to become completely iilled with .water, sothat noair is wasted in iilling an air'- space with' air at pumping pressure.YIn order to allow for the'escape of the air from the domes 100 afterthey have become watersealed from the discharge-ports, I provide themwith valves 101. (Shown in detail in Fig. 10.) Each of the valves 101consists of a lower or main part 102 and an upper vpart or screwcap 103.In the cap 103 are formed a number of openings 10a, arranged around acentral opening in which is securedv a rod 105, provided witha head 106.Sliding ou the rod 105 is a disk 107, of rubber or other suitablematerial. While the chambers are filling, the air passes upwardly aroundthe'disk 107 and through the openings 101 without disturbin g thesaiddisk. When the compressed air is admitted t0 the chamber at pumpingpressure, however, the force is sufficient to raise the disk 107 againstthe lower face of the cap 103 and close the openings 104.

The primary valves 97 are operated automatically by the iioats 93 andweights 90 in a manner to 1bve-hereinafter described. It is sometimesdesirable,however,to operate these valves manually. This is done by'devices which will now bedescribed. On one side ot' the box or case 68ot' each of the primary valves is secured a screw-plug 110, Fig. 11,through which passes a rock-shaft 111. Se-

cured to or formed integral with the inner end of the rock-shaft 111 isan enlarged portion 112, which is provided with two arms 113. The arms113, Fig. 14, embrace a pin 114, which is secured -to the bell-cranklever S1. The arms 113 are such a distance apart as to allow thebell-crank lever 81 to perform its usual travel without causing the pin11iC to come in contact with the said arms. Secured to the outer end ofthe rock-shaft 111 is a bell-crank lever 115. The vtwoadjacent arms ofthe bell-crank levers 115 are ccnnected by a rod or link 116, Fig. 16,and the outer arms of the saidlevers have attached to them suitablewires or rods 117which extend upwardly, so that they can he manuallyoperated. The side off'the box or casing 68 120, Fig. 17, represents thereservoir of the I aircompressor, which supplies the air for operatingthe pump. The pipe 56A, leading to the main valve 4G, is connected witha pipe 56B, which communicates with the reservoir 120, and between thepipes 56A and 56B is a throttle-valve 121, by means ot' which the supplyof air through the pipe 6A to the valvecasing 46- may be diminished or,if desired, completely shut ott. The valve 121 may be operated by meansof a hand-wheel 122 or by any other suitable means. should be placed ata point within access of the operator and may be placed near thereservoir 120, 'as shown in the drawings, or at any desired distancefrom said reservoir, provided access may be had to it. The supplypipe76, leading to the primary valves 67, is connected with the pipe 56B,between the reservoir 120 and the valve 121, so that theoperation otthevalve 121 will not in any way affect the supply of air passing throughthe pipe 76, or, if so desired, the pipe 76 may be connected to thereservoir 120 independently of the pipe 56B, as the same result may heobtained in this manner. The rate of discharge of the pump is regulatedby the valve 121,

as the farther this valve is opened the greater will be the pressure inthe pipe 56A, and consequently the more rapid the discharge of the pump.In practice the valve 121 is rarely, if ever, completely opened, as itis desirable to have the pressure in the reservoir somewhat higher thanthat required for pumping. It follows from this that the pressure in thepipe The valve 121 76 is higher than that in the pipe 56A. This,

for reasons which will be hereinafter eX- plained, is an importantfeature in obtaining some of the objects of my invention.

The operation of my pump is as follows: supposing the parts to be in theposition shown in Fig. 1 and the chamber 21 full of water and thechamber 22 empty,the compressed air, passing down the pipe 56A to thevalve-casing L1.6,enters the chamber 21 through the port 43, driving thefloat-valve 63 downward as it enters. f This will force the watercontained in the chamber 21 up through the pipe 35, valves 38, andconnecting-pipe 39 to the ldischarge-pipe 40. At the same time the port43, leading to the chamber 22, being opened through the valve 50 to theexhaustport 114, the air contained in the said chamber 22 will pass -outthrough said ports and IIO allow the water surrounding the pump to en- Yter the chamber 22 through the inlet-valves 27 and openings 24. As thewater falls in the chamber 21 the floaty 93 will fall with it untildetained by means of the stop 9:1; As the rod 01 of the iioat 93 isbelow the pin 85 ot' the bell-crank lever 81, the downward motion ot'Said float 03 in the chamber 21 will not in any Way affect the saidbell-crank lever, and as the waterrises in the chamber 22 the weight 90in said chamber will rise with it untilprevented by the stop 95. Theslot 86 in the upper end of therod 87 will allow the weight 90 to riseWithout affecting the bellcrank lever 81 of the primary valve 67connected with the chamber 22. When the water in the chamber 2l hasfallen to near the end of the pipe 35, the weight 90 will descend withit and by means of the rod 87 will pull the end of the bell-crank lever81 downward and force the piston 72 of the valve 67 outwardly, thusconnecting the air-pipe with the air-supply pipe 76. The air will nowpass from the supply-pipe 76 through the pipe 70 into the right-hand endof the main valve 46. As the left-hand end of the main-valve casing 46is in communication through the ports 51 and 43 with the chamber 21,which contains air at pumping pressure, which pressure, as has beenhereinbefore explained, is less than that supplied by the pipe 76, thepiston 48 will be forced toward the left-hand end of the valve 46 untilthe left-hand port 43 is closed. At the same time the end of the piston48 will close the left-hand port 5l and shut off communication betweenthat end of the valve-casing 46 and the chamber 21. The pressure willthen immediately rise in this end of the valve-casing until equal tothat in the opposite end, as both are now in communication with theair-supply pipe 76. This will hold the piston 48 and valve 50 in thisposition until the chamber 22 is completely filled with water, the valve50 being in a reversed position to that shown in Fig. 3, so that theright-hand port 43 will still be in communication with the exhaust 44.As soon as the chamber 22 is completely filled the float 93 at that endwill be forced upward into the dome 100 and by means of the pin 85 willforce upwardly the end of the bell-crank lever 81, thus drawing thepiston 72 of the valve y67 inwardly and connecting a pipe 71 with theexhaust 76A, thus exhausting the air from the left-hand end of the valve-casing 46. This will immediately cause the piston 48 to move farthertoward the left until the righthand port 51 is put into communicationwith the right-hand end of the valve-casing 46. The compressed air willnow pass down through the port 51 into the port 43 and gradually tillthe same up to the pumping pressure without causing any jar or shock 0naccount of the contracted opening 53. As the opening 53, however, islarger than the supply-opening, the valve will remain in this positionuntil the air in port 43 is raised to practically working pressure, whenit will force the piston 48 completely to the left, thus connecting theright-hand port 43 with the airsupply and the left-hand port 43 with theexhaust. The above operation will then be reversed, the water beingforced out of the chamber 22 and allowed to enter the chamber .21. Itwill be seen by reference to Fig. 2 that the above-described operationcould not be properly performed if there were no play between the piston48 and valve 50, for if the valve 50 were rigidly secured to the pistonthe port 43 would be opened at practically the same time as the port 51.It is to be understood, however, that in the operation of the pump theparts are never in the position shown in Fig. 2, for when the piston 48is in the position shown in Fig. 2 the valve 50 is either in theposition shown in Fig. 3 or in the reversed position, andrwhen the valveis in the position shown in Fig. 2 the piston will be in such a positionas to uncover one of the ports 51.

In the above operation if the chamber 22 had become filled with waterbefore the chamber 21 had become emptied the operation would be thesame, except that the piston 48 would make but a single stop in itstravel, for when the chamber 22 became filled and by raising the Iioat93 connected the lefthand end of the valve 46 with the exhaust therewould be noV movement of the piston 48, as the right-hand end of thesaid valve would also be connected with the exhaust, so that when thechamber 21 was emptied and connected the right-hand end of the valve 46with the air-supply the said Valve wouldmove over until it uncovered theright-hand port 51 and allowed the compressed air to pass down the same.In this case the valve 52 in the left-hand port 51 would be forcedupwardly to close the opening 53, leading from said port to theleft-hand end of the valve 46, and thus prevent the said end from beingfilled with air at the pumping pressure, or otherwise the operation ofthe pump would be delayed until enough air was exhausted from thechamber 21 to reduce the pressure considerably below the pumpingpressure.

In case the piston 48 became clogged by sediment during a period ofdisuso it might be found that the pump would not operate when thecompressed air was turned on. In this case the air would first becompletely closed from the supply-pipe 56A by means of thethrottle-valve 121. This, asl previously described, would not interferewith the supply of air through the pipe 76 to the primary valves 67.These valves could now be ,operated by alternately pulling upwardly onthe two wires 117. This would throw the airpressure rst on one and thenthe other end of the piston 48 until the same became loosened, when theair could be tu'rnedon the supply-pipey 56A, so that the pump couldproceed to operate automatically.

In an application, Serial No. 678,462, filed by me April 22, 1898, Ihave claimed the combination, with two Valved chambers, of a main valvefor controlling the admission of air to and exhaust thereof from saidchambers and means for alternately and independently connecting each endof said main valve with the air supply and exhaust by the rise and fallof the liquid in said chambers. In said appli- IOS) IIO

cation I have also claimed the combination, with a chamber forcontaining liquid to be raised, of an air-supply, a valve controllingthe admission of air from said air-supply to said chamber through a mainport, a secondary port, and means for opening said latternamed port bythe initialmovement of said valve. In said application I have alsoclaimed the combination, with a chamber for contain ing the liquid to beraised, of a, main air: supply, a mainy valve controlling saidairsupply, a separate and independently-controllable air-supply foroperating said main valve, an auxiliary valve to control said airsupply,mechanism for automatically operating said auxiliary valve, and meansfor manuallyoperating said auxiliary valve when said main air-supply iscut off.

Having now fully described my invention what I claim isl. In acompressed-air water-elevator, two chambers each provided with a valvedinlet and a valved discharge, two main air-ports, one communicating witheach chamber, a suitable air-supply adapted to be putin communicationwith said main air-ports, an exhaustport also adapted to be putincommunication with said main air-ports, a valve for closing oi the mainair-port-in communication with an emptied chamber from both theair-supply and the exhaust while the main air-port of thefilling-chamber is in communication with the exhaust, and means formaintaining said latter communication until said latter chamber isfilled.

2. In a compressed-air water-elevator, two chambers each provided with avalved inlet and a valved discharge, two main air-ports, onecommunicating with each chamber, a suitable air-supply adapted tobe putin communication with said main air-ports, an exhaustport also adaptedto be putin communication with said main air-ports, a valve arranged toclose oi the main air-port of the emptied chamber from both theair-supply and the exhaust while the main air-port of the fillingchamberis in communication with the exhaust, and means for retaining said valvein said position until said latter chamber is filled.

3. In a compressed-air water-elevator, two chambers, each provided witha valved inlet and a valved discharge, two main air-ports, onecommunicating with each chamber, an air-supply, an exhaust, a valveadapted to alternately connect each of said main air-ports with theair-supply and with the exhaust, secondary air-ports for supplying airto said chambers to raise the pressure in the same, a piston controllingsaid secondary ports, and means for actuatingfsaid valve by the movementof said piston to move said valve a less distance than said piston.

4. In a compressed-air water-elevator, two chambers, each provided witha valved inlet and a valved delivery, two main air-ports, onecommunicating with each chamber, an air-supply, an exhaust, secondaryair-ports for supplying air to said chambers to raise the pressure inthe same, a piston acting as a valve for said secondary ports, a valvefor said main ports, and loose connections between said valve and saidpiston, whereby said piston will move a greater distance than saidvalve.

5. In a compressed-air water-elevator, two chambers each provided with avalved inlet and a valved discharge, two main air-ports, onecommunicating with eachchamber,amain air-supply adapted to furnishcompressed air to said main airports, a suitable valve controlling theadmission of air to said main ports, a piston for actuating said valve,a secondary air-supply adapted to supply air at a higher pressure thansaid main air-supply for moving said piston,passageways between saidsecondary air-supply and said main ports, and means for closing saidlatter-named passageways while one of said main ports is cut olf fromthe main air-supply and the other of said main ports is in communicationwith the exhaust.

In testimony whereof I have hereunto set my hand and affixed my seal inthe presence of the two subscribing witnesses.

MAI-tous L. MITCHELL. [n s] lVitnesses:

W. A. ALEXANDER, A. C. FowLnn.

